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RE: Subject: RE: wsdl:types and arrays

From: Don Mullen <donmullen@tibco.com>
Date: Thu, 12 Dec 2002 10:02:23 -0500
Message-ID: <339902DC0E58D411986A00B0D03D843201B2496A@extmail.rtp.tibco.com>
To: "'mats_henricson@yahoo.com'" <mats_henricson@yahoo.com>, www-ws-desc@w3.org, Don Mullen <donmullen@tibco.com>, ryman@ca.ibm.com, mgudgin@microsoft.com, anne@manes.net, jacek@systinet.com, sanjiva@watson.ibm.com


The book is wrong, although somewhat understandably given the WSDL 1.1 text.

FYI: Current status quo of WSDL 1.2 is that it won't directly support SOAP
encoding.

That said, we do have a problem with current WSDL 1.2 public and editor's
copy specification:

3.4.1 Guidelines for Using XML Schema
"Array types should extend the Array type defined in the SOAP v1.1 encoding
schema "http://schemas.xmlsoap.org/soap/encoding/" (regardless of whether
the resulting form actually uses the encoding specified in Section 5 of
[SOAP 1.1])."

This should be cleaned up.

Don

-----Original Message-----
From: Mats Henricson [mailto:mats_henricson@yahoo.com]
Sent: Thursday, December 12, 2002 1:12 AM
To: www-ws-desc@w3.org; donmullen@tibco.com; ryman@ca.ibm.com;
mgudgin@microsoft.com; anne@manes.net; jacek@systinet.com;
sanjiva@watson.ibm.com
Subject: Subject: RE: wsdl:types and arrays 

Hi!

My concern about wsdl:types being incompatible with XSD
maxOccurs='unbounded' comes from the book "Building Web
Services with Java", published in December 2001 by SAMS,
ISBN 0-672-32181-5.

On page 341 it says:

   Normally, to define a type that contains a repeating
   group of elements, you would use the following style
   of XML schema:

     <xsd:complexType name="registrationRequest">
       <xsd:sequence>
         <xsd:element name="items"
            type="xsd:string" maxOccurrs="unbounded" />

   However, in WSDL, repeating groups such as this must
   be modeled using the array data type from the SOAP
   encoding namespace
   (xmlns:soapenc="http://schemas.xmlsoap.org/soap/encoding/").
   This is another jarring example where an aspect of
   the message encoding (really the domain of the binding
   element, as we will see in the next section) imposes
   itself on the base datatyping mechanism in WSDL. This
   is an artifact of the common use of WSDL to model SOAP
   messages. So, regardless of weather your Web service
   uses SOAP, you need to use the array datatype from the
   SOAP encoding namespace to model repeating groups. The
   following snippet shows the registrationRequest type:

     <xsd:complexType name="registrationRequest">
       <xsd:sequence>
         <xsd:element name="items">
           <xsd:complexType name="ArrayOfItem">
             <complexContent>
               <restriction base="soapenc:Array">
                 <attribute ref="soapenc:arrayType"
                   wsdl:arrayType="xsd:string[]"/>
               </restriction>
             </complexContent>
           </complexType>
         </xsd:element>

OK, the book is old (one year), and it may be flat out
wrong, but the text that assumedly describes this
restriction, section 2.2 in the old version of WSDL, has
not been changed.

So, this leaves us with two possibilities:

1. The book is wrong
2. The book is right

I assumed the book was right, which made me send you the
original message.

If the book is wrong, then why do we have a section in
the standard that talks about this? Why can't we just
totally throw away that text and replace it with a blank
statement that any valid XSD can be in the wsdl:types
section in a WSDL file? The troubling text is:

   Array types should extend the Array type defined in
   the SOAP v1.1 encoding schema...

I'm not sure if "should" means what it does, according to
IETF RFC 2119. Can I use my maxOccurrs="unbounded" any
way I want?

Mats

PS. Sorry for late reply. I just got myself a new job,
    plus a dead computer at home.



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Received on Thursday, 12 December 2002 10:06:08 GMT

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